Background

Rising life expectancy and rising mortality are contradictory, and aging is a critical period in human life during which changes occur in internal and external organs. These changes cause the individual to adapt to the environment. Throughout the world, the world's geriatric population is rising as increasing life expectancy, declining mortality, and birth rates. Also, the number of people over the age of 60 is growing faster than other age groups. With this significant increase in the older people, improving their health and well-being is a priority [1]. According to studies, the geriatric population will increase from 600 million in 2000 to 1 billion and 200 million in 2025 [2].

One of the most common and serious problems among the older people is falling [1]. According to the World Health Organization (WHO), a fall is defined as an event that results in a person coming to rest inadvertently on the ground or floor or other lower level [3]. Injuries from falls can be fatal or non-fatal. Falls are associated with reduced quality of life and higher costs of health care. At older ages, the health effects and costs of falls are increasing significantly worldwide [4].

The fall can be due to factors such as medication, osteoarthritis, depression, dizziness, and disturbances in balance and gait (due to cerebellar damage or in connection with age-related degenerative changes in the middle and inner ear). Muscle weakness due to aging or medication can cause falls as well. The use of assistive devices, age over 80 years, postural hypotension and impaired vision (decreased adaptive power, lens opacity), and chronic diseases are among the causes of falls [5,6,7].

Injuries due to falls may lead to a decrease in the ability to perform activities of daily living [8]. Falls, especially in the older people, increase disability, and the injured people often do not recover to their previous functional level [9, 10]. In addition to physical injuries, falls also have psychological consequences [11]. In addition to physical injuries, falls also have psychological consequences [11]. Many people who have experienced a fall are afraid of falling, which in turn leads to immobility, followed by pressure ulcers, rhabdomyolysis, pneumonia, weakness, and increased risk of falls [12, 13]. Serious injuries caused by falls include fractures, especially pelvic and thigh fractures. Also, most injuries occur in the lower limbs, upper limbs, head, and trunk, which most of them are bruises or cuts, fractures, and dislocations [14, 15].

Among them 5% lead to fractures and 5–10% to other injuries. Among the causes of hospitalization, hospitalization due to fall is 5 times more than hospitalization due to other injuries [16]. The prevalence of falls in people over 65 is 30% in the USA, 13.7% in Japan, 26.4% in China, and 53% in India [17]. Research has also shown that the prevalence of falls is higher in older women than men [18].

The average fall in a nursing home is 1.5 falls per year per bed. Investigating and reducing risk factors reduces the risk of falls. Regular assessment in a nursing home can help identify high-risk patients [19]. The evaluation includes fall conditions, the patient's complete physical history, and search for possible risk factors. One of the most effective strategies for preventing falls is multi-factor interventions aimed at identifying risk factors, muscle strengthening exercises with balance training, and quitting psychedelic drugs [20, 21].

Methods

Searching strategy and study selection

The present study was conducted to investigate the prevalence of falls in the older people worldwide via systematic review and meta-analysis. To collect data in this study, international databases, Scopus, Web of Science, PubMed, Science Direct, Google Scholar, SID, Magiran were sought without any time limit until August 2020. The search process was carried out in the mentioned databases using the English keywords, "Prevalence;" "Fall"; "Slip"; "Older people"; "Older adult"; and the Persian keywords Fall; Accidents; Older people; and their possible combinations in international bases. For instance, how to search the PubMed database is described in the box below. To study the Gray literature, the review of related sites was also on the agenda. To maximize the comprehensiveness of the search, the list of the sources used in all related articles that were found in the above search was manually reviewed. Initially, the duplicate studies in various searched databases were excluded from this study. Then, the researchers of this study prepared a list of titles of all the remaining articles to obtain eligible articles by evaluating the articles in this list. In the first stage, screening, the title, and abstract of the remaining articles were carefully studied, and irrelevant articles were removed based on the inclusion and exclusion criteria. In the second stage, the evaluation of the suitability of the studies, the full text of the possible relevant articles remaining from the screening stage was examined based on the inclusion and exclusion criteria and in this stage, unrelated studies were eliminated. To avoid bias, all steps of reviewing sources and extracting data were performed by two researchers independently. In case any articles were not included, the reason for deleting them was mentioned. In cases where there was disagreement between the two researchers, the article was reviewed by a third party. A total of 104 studies entered the third stage, i.e., qualitative evaluation.

PubMed Search Strategy: (prevalence[Title] OR outbreak[Title]) AND (fall down[Title] OR slip[Title] OR fall[Title] OR damage[Title] OR accidental fall[Title] OR injury[Title] AND (older people[Title] OR older adult[Title] OR aged[Title]) OR (fall down[Title] AND older people[Title]) OR (slip[Title] AND older adult[Title]) OR (accidental fall[Title] AND aged[Title]).

Inclusion and exclusion criteria

Inclusion criteria include: 1—cross-sectional studies, 2—studies that have studied the prevalence of falls in the older people worldwide, 3—observational studies (non-interventional studies), 4—Persian studies, 5—English studies, and exclusion criteria include: 1—case–control studies, 2—cohort, 3—case report, 4—interventional studies, 5—letter to editor, 6—studies whose full text is not available, 7—duplication of studies, 8—systematic review and meta-analysis studies.

Qualitative evaluation

To validate and evaluate the quality of articles (i.e., methodological validity and results), a checklist appropriate to the type of study was used. The STROBE checklist is commonly used to critically and qualitatively evaluate observational studies such as the present study. The STROBE checklist consists of six general scales/sections: title, abstract, introduction, methods, results, and discussion. Some of these scales have subscales, and in total, this statement contains 32 items. In fact, these 32 items encompass various methodological aspects of the study, including title, problem statement, study objectives, type of study, the statistical population of the study, sampling method, determining the appropriate sample size, definition of variables and procedures, data collection tools, statistical analysis, and findings. Accordingly, the maximum score obtained from the qualitative assessment in the STROBE checklist will be 32. Considering the score of 16 as the cutoff point, those articles obtaining a score of 16 and above will be considered as articles with suitable and average methodological quality, and those obtaining below 16 were considered as poor and were therefore excluded from the study.

Extracting the data

The information related to all selected articles which were entered into the systematic review and meta-analysis process was extracted from a pre-prepared checklist. This checklist includes the title of the article, the name of the first author, the year of publication, the country, the sample size, the number of falls per sample, the average age of the sample, and the prevalence and continent percentage.

Statistical analysis

I2 test was used to evaluate the heterogeneity of selected studies. To investigate the dissemination error, due to the large statistical sample size included in the study, Begg and Mazumdar test was used at a significance level of 0.1 and its corresponding Funnel plot. The data were analyzed using the Comprehensive Meta-Analysis Software (Version 2).

Results

Study selection and data extraction

This study examined the prevalence of falls in the older people of the world through systematic review and meta-analysis. After searching in various databases, from a total of 4251 articles, 1795 articles from the PubMed database, 172 articles from the Science Direct database, 160 articles from the Scopus database, 160 articles from Web of Science database, and 1720 articles from Google Scholar database, 136 articles from Magiran database, and 111 articles from SID database were selected for the study. Out of a total of 4251 identified studies, 66 were duplicate and were excluded. In the screening stage, out of 4185 studies, 3651 articles were excluded through studying the title and abstract sections based on inclusion and exclusion criteria.

In the competency assessment stage, out of 540 studies, the remaining 436 articles were excluded regarding the inclusion and exclusion criteria due to being irrelevant through perusing the full text of the articles. In the qualitative evaluation stage, through studying the full text of the articles and based on the STROBE checklist, out of the remaining studies, no article was removed due to the poor methodological quality.

The studies were reviewed based on the four-step PRISMA 2009 process, including article identification, screening, review of article acceptance criteria, and finally, the articles entered to the meta-analysis (Fig. 1). Ultimately, 104 studies were included in the final analysis, the information of which was mentioned in the tables (Table 1) [14, 19, 22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123].

Fig. 1
figure 1

The flowchart on the stages of including the studies in the systematic review and meta-analysis (PRISMA 2009)

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Table 1 The extracted data from the final studies entered into the meta-analysis
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The probability of bias in the dissemination of fall outcomes in the older people of the world by Funnel plot and Begg and Mazumdar test at a significance level of 0.1 indicated no dissemination bias in the present study (P = 0.101) (Fig. 2).

Fig. 2
figure 2

Funnel plot results of the prevalence of falls in the older people worldwide

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Based on the test results (I2: 99.9) and due to the heterogeneity of selected studies, a random-effects model was used to combine the studies and the shared prevalence estimate. The reason for heterogeneity between studies can be due to differences in sample size, sampling error, year of study, or place of study. Out of the 104 articles submitted for systematic review and meta-analysis with a sample size of 1,741,613 patients, 48 studies were conducted in Asia, 16 studies in Europe, 2 studies in Africa, 32 studies in America, and 6 studies in Oceania. The smallest and highest sample sizes were related to the studies of Aktaş, S. et al. (2004) (n = 32) [23] and J.A. Steven et al. (2008) (n = 922,200) [38]. The characteristics of the eligible studies shown in the meta-analysis are given in Table 1.

Meta-analysis

According to the results of the present study, the prevalence of falls in the world's older people was 26.5% (95% CI 23.4–29.8%). The midpoint of each line segment shows the prevalence in each study, and the diamond shows the population prevalence for the entire studies (Fig. 3).

Fig. 3
figure 3

The prevalence of falls in the world's older people and 95% confidence interval based on a random-effects model

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Meta-regression test

To investigate the effects of potential factors in the heterogeneity of the prevalence of falls in the older people in the world, meta-regression was used for the two factors of the sample size (Figs. 4, 5). According to Fig. 4, with increasing sample size, the prevalence of falls in the older people of the world decreases, which there is a statistically significant difference (P < 0.05). It was also reported (Fig. 5) that with the increase in the research year, the prevalence of falls in the older people of the world decreases, which there is also a statistically significant difference (P < 0.05).

Fig. 4
figure 4

Meta-regression chart of the prevalence of falls in the older people of the world by sample size

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Fig. 5
figure 5

Meta-regression chart of the prevalence of falls in the older people of the world by the year

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Subgroup Analysis

Table 2 reports the prevalence of falls in the world's older people in Asia, Europe, Africa, and America and Oceania. The highest rate of prevalence of falls in the older people was related to Oceania with 34.4 (95% CI 29.2–40) and America with 27.9 (95% CI 22.4–34.2) (Table 2). Table 2 is based on the studies performed, and in order to reduce the heterogeneity created in the whole study, as reported in Table 2, the number of studies does not have the same distribution and therefore the higher or lower prevalence in a continent. It is based only on studies of that continent.

Table 2 Prevalence of falls in the older people of the world according to different continents
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Discussion

Out of the 104 articles submitted for systematic review and meta-analysis with a sample size of 1,741,613 people, 48 studies were conducted in Asia, 16 studies in Europe, 2 studies in Africa, 32 studies in America, and 6 studies in Oceania. According to the results of the present study, the prevalence of falls in the world's older people was 26.5% (95% CI 29.4.8%). To investigate the effects of potential factors in the heterogeneity of the prevalence of falls in the older people in the world, meta-regression was used for the two factors of the sample size. According to it, with increasing sample size, the prevalence of falls in the older people of the world decreases, which there is a statistically significant difference (P < 0.05). Also, with the increase in the research year, the prevalence of falls in the older people of the world decreases, which was also statistically significant (P < 0.05). According to the results of subgroup analysis, the highest prevalence of falls in the older people was related to Oceania with 34.4% (95% CI 29.2–40%) and America with 27.9% (95% CI 22.4–34.2%).

Falls are common among the geriatric population; this incident is one of the main causes of disability and death among these people [43, 45]. It is said that those who fall and are not harmed often suffer the negative consequences of that fall. Older people who fall are more likely to fall within a year. These people are also more at risk of falling. This fear of falling can lead to depression and limitation of movement [38].

A study by Boyd, R. et al. showed that 3.5 million people, or about 10 percent of the older people in the USA, have fallen in the past three months. About 1.7 million people were injured, and 875,000 of the injured people went for medical treatment. Based on the results of this study, 12.9 million, or 36%, of the older people in the USA are relatively afraid of falling. According to this study, there is a significant relationship between falling and fear of falling. Among those who recently had a fall, 16% feared a severe or moderate fall; however, only 6% of these people were not afraid or were a little afraid [38].

According to a study by Cevizci, S. et al., those who do not walk at home or out of the house, or walk less, and those who cannot meet their daily needs, have a higher risk of falling than other people. It was also asserted that those who have at least one case of chronic disease, or people with physical and mental impairment, or people with lower quality of life, are at higher risk of falling [40].

The study by Handrigan et al. showed that, according to the dose–response relationship between BMI and prevalence, underweight and obese people were reported to be more common among men. For women, unlike men, obesity was not significantly linked with a higher prevalence of falls [56].

The results of a study carried out by Habibeh Ahmadipour in Kerman, Iran, found that more than a quarter of the older people who referred to the comprehensive health service centers and bases in Kerman during the past 6 months had a history of at least one fall and more than 10 percent also had a history of falling more than once [106]. In astudy by Habibeh Ahmadipour and et al, it was stated that the use of more than four drugs, the use of inappropriate shoes, and the presence of underlying disease were the most common risk factors for health-related in the older people, respectively [106].

With the increase in the elderly population, the need for more care of this population for fractures has increased, because fractures greatly reduce the quality of life of the elderly [107]. Among fractures, pelvic fractures, which occur due to falls in the elderly, are significant, and reports indicate that one-third of patients do not survive more than a year after pelvic fractures [107]. Primary prevention to reduce fractures in the elderly can be done by reducing falls and strengthening bones by eliminating risk factors or by medication [124].

Conclusion

In conclusion, it is stated that due to the increasing percentage of the world's aging population, the problem of falls, as a common problem with adverse consequences, needs to be seriously considered by policymakers and health care providers to make appropriate plans for interventions and take precautions to reduce falls in the older people. Most of the reasons that lead to falls in the elderly are related to the living environment of the elderly, and by following simple tips and providing assistive equipment to the elderly, the risk of falls in the elderly can be significantly reduced, so appropriate policy to create appropriate living environment for the elderly, such as proper lighting of the house and avoiding total darkening of the house, use of bath chairs and toilets, use of appropriate shoes, not walking after taking sleeping pills, regular eye examinations in the elderly, not carrying heavy equipment, making the phone available, and installing handles in different parts of the house, can help prevent falls in the elderly.